/*
 * Copyright 2004 Clinton Begin
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package top.jfunc.common.db.scriptrunner;

import java.io.IOException;
import java.io.LineNumberReader;
import java.io.PrintWriter;
import java.io.Reader;
import java.sql.*;

/**
 * Tool to run database scripts
 */
public class ScriptRunner{

    private Connection  connection;
    private String      driver;
    private String      url;
    private String      username;
    private String      password;

    private boolean     stopOnError;
    private boolean     autoCommit;

    private PrintWriter logWriter      = new PrintWriter(System.out);
    private PrintWriter errorLogWriter = new PrintWriter(System.err);

    /**
     * Default constructor
     */
    public ScriptRunner(Connection connection, boolean autoCommit, boolean stopOnError){
        this.connection = connection;
        this.autoCommit = autoCommit;
        this.stopOnError = stopOnError;
    }

    public ScriptRunner(String driver, String url, String username, String password, boolean autoCommit,
            boolean stopOnError){
        this.driver = driver;
        this.url = url;
        this.username = username;
        this.password = password;
        this.autoCommit = autoCommit;
        this.stopOnError = stopOnError;
    }

    /**
     * Setter for logWriter property
     *
     * @param logWriter
     *            - the new value of the logWriter property
     */
    public void setLogWriter(PrintWriter logWriter){
        this.logWriter = logWriter;
    }

    /**
     * Setter for errorLogWriter property
     *
     * @param errorLogWriter
     *            - the new value of the errorLogWriter property
     */
    public void setErrorLogWriter(PrintWriter errorLogWriter){
        this.errorLogWriter = errorLogWriter;
    }

    /**
     * Runs an SQL script (read in using the Reader parameter)
     *
     * @param reader
     *            - the source of the script
     */
    public void runScript(Reader reader) throws IOException, SQLException{
        try{
            if(connection == null){
                DriverManager.registerDriver((Driver) Resources.classForName(driver).newInstance());
                Connection conn = DriverManager.getConnection(url, username, password);
                try{
                    if(conn.getAutoCommit() != autoCommit){
                        conn.setAutoCommit(autoCommit);
                    }
                    runScript(conn, reader);
                }
                finally{
                    conn.close();
                }
            } else{
                boolean originalAutoCommit = connection.getAutoCommit();
                try{
                    if(originalAutoCommit != this.autoCommit){
                        connection.setAutoCommit(this.autoCommit);
                    }
                    runScript(connection, reader);
                }
                finally{
                    connection.setAutoCommit(originalAutoCommit);
                }
            }
        }
        catch(IOException|SQLException e){
            throw e;
        }
        catch(Exception e){
            throw new NestedRuntimeException("Error running script.  Cause: " + e, e);
        }
    }

    /**
     * Runs an SQL script (read in using the Reader parameter) using the
     * connection passed in
     *
     * @param conn
     *            - the connection to use for the script
     * @param reader
     *            - the source of the script
     * @throws SQLException
     *             if any SQL errors occur
     * @throws IOException
     *             if there is an error reading from the Reader
     */
    private void runScript(Connection conn, Reader reader) throws IOException, SQLException{
        StringBuffer command = null;
        try{
            LineNumberReader lineReader = new LineNumberReader(reader);
            String line = null;
            while((line = lineReader.readLine()) != null){
                if(command == null){
                    command = new StringBuffer();
                }
                String trimmedLine = line.trim();
                if(trimmedLine.startsWith("--")){
                    println(trimmedLine);
                } else if(trimmedLine.length() < 1 || trimmedLine.startsWith("//")){
                    // Do nothing
                } else if(trimmedLine.length() < 1 || trimmedLine.startsWith("--")){
                    // Do nothing
                } else if(trimmedLine.endsWith(";")){
                    command.append(line.substring(0, line.lastIndexOf(";")));
                    command.append(" ");
                    Statement statement = conn.createStatement();

                    println(command);

                    boolean hasResults = false;
                    if(stopOnError){
                        hasResults = statement.execute(command.toString());
                    } else{
                        try{
                            statement.execute(command.toString());
                        }
                        catch(SQLException e){
                            e.fillInStackTrace();
                            printlnError("Error executing: " + command);
                            printlnError(e);
                        }
                    }

                    if(autoCommit && !conn.getAutoCommit()){
                        conn.commit();
                    }

                    ResultSet rs = statement.getResultSet();
                    if(hasResults && rs != null){
                        ResultSetMetaData md = rs.getMetaData();
                        int cols = md.getColumnCount();
                        for(int i = 0; i < cols; i++){
                            String name = md.getColumnName(i);
                            print(name + "\t");
                        }
                        println("");
                        while(rs.next()){
                            for(int i = 0; i < cols; i++){
                                String value = rs.getString(i);
                                print(value + "\t");
                            }
                            println("");
                        }
                    }

                    command = null;
                    try{
                        statement.close();
                    }
                    catch(Exception e){
                        // Ignore to workaround a bug in Jakarta DBCP
                    }
                    Thread.yield();
                } else{
                    command.append(line);
                    command.append(" ");
                }
            }
            if(!autoCommit){
                conn.commit();
            }
        }
        catch(SQLException|IOException e){
            printlnError("Error executing: " + command);
            printlnError(e);
            throw e;
        }
        finally{
            conn.rollback();
            flush();
        }
    }

    private void print(Object o){
        if(logWriter != null){
            System.out.print(o);
        }
    }

    private void println(Object o){
        if(logWriter != null){
            logWriter.println(o);
        }
    }

    private void printlnError(Object o){
        if(errorLogWriter != null){
            errorLogWriter.println(o);
        }
    }

    private void flush(){
        if(logWriter != null){
            logWriter.flush();
        }
        if(errorLogWriter != null){
            errorLogWriter.flush();
        }
    }

}
